Pneumatic tool.



G. H. GILVIAN.

PNEUMATIC TOOL. APPLICATION .FILED IAN. 2. 190B.

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G. H'. Gun/IAN. PNEUMATIC TOOL.

APPLICATION FILED IAN-2,1908.- L.,

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y G. H. GILIVIAN.

PNEUMATlc TooL,

APPLICATION FILED JAN.2. 1908. 1,159,62@ Patentedsept. 7,1915.

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PNEuM/mc roof.

I APPLICATION F|LED H\N.2, 1908. 1,152,624., l l PatentedSept. 7, 1915.

`4 SHEETS-SHEET 4.

GEORGE H. GILMAN, CLAREMONT NEW HAMPSHIRE, ASSIGNOR, BY MESNE ASSIGN-MENTS, T SULLIVAN MACHINERY COMPANY, 0F.' BOSTON, SSACH'USETTS, A COB-FQRATION OF MASSACHUSETTS.

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Patented Sept.. '3, 1915.

Application led January 2, 1908. Serial No. 408,877.

To all whom it may concern.' l

Be it known that l, GEORGE H. GILMAN, a citizen of the United States,residing at Claremont, in the county of Sullivan, State of New Hamshire, have invented anA Improvement in neumatic Tools, of which theV'following description, .in connection with which may be made of myinvention,

' and valve block on the line the accompanying drawings, isaspecification, like letters on the drawings representingv like parts. lMy invention relates to pneumatic or other pressure -lluid actuatedtools, being more particularly intended to provide a tool having two Vormore tool-actuating units together with suitable means for controllingor regulating the operation of said units.

While my invention in its broader aspects may be embodied inconstructions other than the one herein shown, in the illustratedembodiment thereof the same is disclosed as applied to a duplex tool ofthedpneumatic piston-hammer type.

I have also shown the same as more particularly intended for -employmentin con.- nection with the surfacing vor dressing of stone, but this ismerely one ap licatiorii an the latter is in no broad sense restrictedto this particular use.

My reference to the following description when taken in connection withthe accompanying illustration of one specific .embodiment thereof, whileits-scope will be more particularly pointed out in the appended claims.

1n the drawings: Figure 1 is a central, sectional elevation takenthrough the working cylinders and controlling valve of a duplexhammer-tool'embodylng one orm of my invention; Fig. 2 is a similarsection taken in a plane at right-angles to the view shown in Fig. 1;Fig. 3 is a detailv showing the regulating valve ina posltion diiierentfrom that in Fig. 1; Fig. 4 is another 'detail showing the regulatingvalve in a third position; Fig. 5 is a plan in section taken on the line5-'5 in Fig. 1; Fig. 6\is a section in plan taken through the workingcylinders on the line 6-6 in Figs. 1 and 2; Fig. 7 is a sectionalelevation taken through the valve 7-7 in Figs. 1 and 5; Fig. 8 is a.detail showing the regulating valve witha portlon of the valve stemattached; Fig. 9 is a section on the line 9-'9 invention will be bestunderstood by' in Fig. 8; Fig. 10 is a section on.v the line l0-1() inFig. 8; Fig. 11 is a section -on the llne 11-11 in Fig. 8; Fig. v12 is ageneralv diagrammatic view showing a developmentl of the pressurepassages relatively to thev 4controlling and regulating valves; Fig. 13

shows the controlling valve in a reverse position from that shown inFig. 12; Fig. 14- shows the regulating valve in adiil'erent positionfrom that shown in Fig. '12 and corresponding to the position shown LinFig. 41;'l Fig. 15 shows the regulating valve'in a third position andlcorresponding to the position shown in Fig.- 3; Fig. 16 is a partialside elevation of ythe duplex tool shown in Fig. 1 showing theregulating valve handle; Fig. 17 is a sectional elevation taken throughthe swivel support for the hammer tool; and F1g..18 shows thedisposition of the tool relatively to the support when employed upon astone surfacing machine..

Referring to the drawings and 'to the illustrated embodiment of myinvention, I- have` shown the same as applied to a pneumatic"A tool ofthe piston-hammer type provided with a pair of working cylinders withtheir coperating andv contained hammer-pistons arranged side by side.Any desired arrangement or construction'of the cylinders and pistons maybe employed, but in the drawings (Fig. 1) the cylinder chambers 1 and 2are shown as formed within a single cylinder casting 3, the'l tter beingprovided with the upper head 4 e osng the upper or l lhead-end of thecylinder and the lower head 5 secured to thelower .end thereof. Thepistons 6 and 7, which may be of any desired construction, are shown asprovided with reduced striking or hammer ends which, as theyreciprocate, are adapted to strike the ends of independent and separatetools 8 and 9, looselyheld within the bushsuch tool is td be employed asa hand tool,

it is desirable toreduce the shock to be sustained by the toolstructure, which shock would ordinarily be increased with the number oftool-actuating units, were the latter toA reciprocate instep and striketheir tools simultaneously.

By the present invention l have arranged the hammer-pistons toreciprocate nonsynchronously or out of step so as to reduce versa, sothat the resultant operation of the duplex4 tool is accompanied by evenless v1- bration andy shock than the'operation of the single tool.

While separatevalves may be employed for the two tool units, or anyother suitable arrangement of controlling device provided, as the'simplest and most effective way of controlling the movements of thepistonhammers, I preferably provide valve means common to the twoworking cylinders, the operation of such valve means providing for amovement of one hammerpiston in one direction as the other,simultaneously executes a movement in the opposite direction. Anysuitable construction of valve may be used, but as shown there isemployed a diEerential pressure-actuated valve located within the valveblock 12, the latter formed in the upper part of the cylinder head 4,and, in turn, surmounted by the endpiece 13, the latter containing thepressure fluid admission passage 14 and the inaoV terconnecting exhaustpassages 15 (Figs. 1 and 2).

Thewaflve v16 maybe of any suitable form but""herein the same is of thepiston type having alternating spaced or circumferential grooves orshoulders, the said grooves being adapted, according to the position ofthe valve, to connect as desired the various pressure passages of thetool. ,The valve l16 works within the suitably apertued valve bushing17, the end of which is closed by the threaded valve cap 18, the latterhaving the plug or stem 19 entering'the hollow. or tubular interior ofthe valve and acting as a guide and support upon which the valve isadapted reciprocatively to slide. The valve has a reduced closedend`-working within a constant pressure chamber 20, the latter connectedby the passage 21 (Figs. 1 and 5) with the admission passage 14, so thatthe valve is constantly pressed toward the cap 18, but may beintermittently moved in the opposite direction and to the position shownin Fig. 1 by. the intermittent admission of the pressure-fluid'to thelarger pressure receiving area at the opposite end of the valve betweenthe same and the cap 18, which admission takes place under the controlof one or the other of the two hammer-pistons through one or the otherof the intermittent pressure-ports 22 and 23 (Figs. 2' and 5).

yIn one position of the valve pressure is admitted to the, head e'nd ofone cylinder and the tool or forward end of the other cylinder, while,at' the vsame time, the head end of the second cylinder and the tool endof the first cylinder are simultaneously opened to the exhaust. Onreverse movement of the valve, which movement is efected by theVconnection of one of theintermittent pressure ports 22 or 23 with alive or constant pressure passage, reverse connections between theadmission and exhaus't and the respective ends of the cylinders areeffected which simultaneously reverse the movements of the two pistons.

For the admission of pressure to and its` exhaust from the head end ofthe cylinders, the cylinder 1 is provided with the passage 24 leading tothe head end of the cylinder and controlled by the controlling valve 16,and the cylinder 2 is provided with a like passage 25. The passage 24leads into an annular groove 26 (see Figs. 1 and 7) in the valve bushing17, and the passage 25 to a similar annular groove 27, and the valve isalso provided with coperating circumferential grooves 28 and 29 throughwhich the said passages are adapted alternately to be placed incommunication with the pressure admission passage 14 as the valve isalternately moved from one position to the other. Next adjacent thegrooves 26 and 27 respectivelyy the valve bushing 17 is also providedwith grooves 30 and 31, which, as shown in Fig, 1, connect directly andconstantly with the exhaust passage 15, so that, with the valve in thepos1tion shown in Fig. 1, when pressure is being admitted to the headend of the cylinder 1, it is being simul` -from the opposite or tool-endof the cylinders 1 and 2 is controlled through the toolend pressurepassages 32 and 33 respectively which, as represented in Figs. 2, 5 and6, extend longitudinally in the walls of the cylinder casting betweenthe piston chambers and enter their respective cylinders through theports 34 and 35 at the lower ends thereof. The tool-end pressurepassages 32 and 33 extend upward through the cylinder head and valveblock (see Figs. 2, 5 and 7) where they have direct connection with theannular grooves 27 and 26 respectively by one or more'horizontalpassages 36 and 37 (see Figs. 5 and 7), so that, when the-passage 24 isopened to the admission passage 14 by the valve 16, the tool-endpressure passage 33 for the tool-end of the other cylinder issimultaneously opened to the admission, and, when the passage 24 isopened to the exhaust, pressure fluid is simultaneously exhausted fromthe tool-end scribed,

arrasar of the opposite cylinder. lin other words, the pressurecontrolling passage for the toolend of each cylinder is so associatedwith1 ment of the two hammer pistons Vin opposed step.

ln the operation of a tool of this typev it may frequently becomedesirable,for reasons which in one specific c'ase are hereinafter morefully referred to, to throw out of operation one of the two hammer-toolswhile continuing to operate the remaining one. 'llo provide such acontrol for the disclosed device l have shownthe same equipped withsuitable regulatingmeans, hereinin the form of a regulating valve 38,which is interposed btween the controlling valve 16 and the twocylinders to control the several passages deand thereby control therelative operation of the two tools. The details of this regulatingvalve will be more. fully de scribed, but its relation to thevalve-reversvat ing passages must now be referred to. `Any desiredmeansmay be employed for -con necting the intermittent pressure passageswith a source of live pressure so as periodically to reverse thecontrolling valve, but in the present instance I have provided constantpressure passages 39 and 40 for the cylinders 1 and 2 respectively,which is each similar in arrangement tothe constant pressure passageordinarily employed in single piston tools of this type. That is to say,the constant pressure assage 39 opens into the cylinder 1 throng a port41 (Figs. 2 and 6), and the passage 40 into thecylinder 2 through a port42, the ports 41 and 42 being locatedl respectively at or about the sameposition lenghtwise the cylinders as the two ports 43 and 44 which openfrom the intermittent pressure passages 22 and 23 into the cylindersland 2 respectively. The

pistons 6 and 7 4being provided with the respective necked-down orreduced portions 45 and 46 the intermittent pressure port 43 wouldordinarily'be opened to live pressurev through the constant pressurepassage 41 when the piston 6 approaches the limit of its downwardmovement in the cylinder 1, and, -on the other hand, the intermittentpressure port. 44 would be placed in'communication with the constantpressure port 43 when the other piston 7 approaches the limit of itsdownward movement.

When the cutting units are operated together as described the constantpressure and intermittent vpressure passagesof one cylinder arepreferably closed by means of the regulating valve 38 as will more fullyappear, and the reversal of the controlling valve 16 is effected bypressure received operatlon of' the instrument, thereby insuring-the'movey spectively,

through the constant sure passages of the other cylinder,-heren thepassages 23V and 40 of the cylinder 2, although the passages of theotherv cylinder might be employed.- equally well if desired. In order toexhaust the pressure from the larger differential area of the valve toreverse .the latter, any suitable means may be employed, but-herein',las is usual in tools of this class, the intermittent pressure passages,in addition to the ports 43 and 44,' lare also provided respectivelywith ports 47 and 48 .(Fig. 2) opening into their respective cylindersVat a point or level below or in advance of the ports 43 land 44, andalso herein-with additional ports 49 and 50 respectively still fartheradvanced.

Considering the simultaneous operation of the tools under the conditionsreferred to,

, that is to say, with the passages 23 and 40 open and the passages 22and 39 closed, pressure would be `admitted through the intermittentpressure port 44 to the larger differential area of the valve near theend of the forward movement of the piston 7 (as represented in Fig. 1),thereby reversing the valve and reversin the movement of the piston ineach tool. n rearward movement of the piston 7 the port 48 in theintermittent pressure passage 23 is soonuncovered and the forward endofthe cylinder 2, at that time being open to the exhaust (as will beexand intermittent presi plained) the pressure will be exhausted fromthe differential area of the valve and the latter reversed to reversethe movements of the two pistons. The additional ports 1,49 and 50opening from the intermittent. pressure passages, of which ports theremay be a still greater number, provide means for varying the length ofthe hammer stroke by varying the instant when, during the backwardstroke of the piston, the intermittent pressure assag'e is openf to theexhaust. 1n place of t is arrangement of auxiliary ports any suitablemeans may be utilized for this purpose, and, in conjunction vwith thedescribed ports, any means for controlling the same may be used. In thepresent instance have shown short slide rods 51 and 52 arranged withinan extension of the intermittent pressure passages 22 and 23 rewiththeir upper ends adapted to act in the capacity of valves to. open orclose the intermittent pressure ports' and thereby render the ports 49and 50 effective or ineffective at will. When the hammers are workedtogether, if' the slide rod 52 is lowered to uncover the port 50 thestroke of the tools is shortened, since the valve is reversed early inthe stroke. To adjust the slide rods,

. the latter are encircled bylspring clips 53 cylinder 2.

' '5 may be exhausted in any suitable way, but

herein, as is customary in'this type of tool, theffor'ward cylinder endsare open to the exhaust throughl the uncovering by their respectivepistons of an appropriately located exhaust'port or ports. The cylinderl is provided with a pair of exhaust ports 57,

andthe cylinder 2wit`h ports 58, the former connected to exhaustpassages 59 and thelatter to exhaust passages 60, which passages extendlengthwise the cylinder casting 3 and the valve block but outside of thecontrol of the regulating valve 38 and the controlling valves 16. Attheir upper ends these exhaust passages connect through grooves 61 and62 (see Fig. 1) in the top of the valve block with the exhaust passages15.

Since the arrangement of the various pressure passages relatively to thevalve chamber and the cylinders for obvious constructionalv reasons arenot completely shown in any one,of the constructional views (Figs. 1-11inclusive), a there is shown in Figs. 12-15 a diagrammatic arrangementof these passages in the form of a development thereof', withoutattempting to portray accurately the mechanical construction which,however, is faithfully shown in the preceding figures referred to.

The operation of the described tool in the` light `of the descriptionalready given will be clear from a consideration of Figs. 12-15. When itis desired to operate the tools simultaneously the regulating valve 38is positioned as depicted in Fig. l12 closing the intermittent pressurepassage 22 and the constant pressure passage 39 leading to the cylinder1, while leavingopen the head end pressure passages 24 and 25 and thetool-end passages 32 and'33 for well as the intermittent pressurepassage 23 and the constant pressure passage 40 for the AUnder theconditions represented in Fig. 12 the piston 7 is at the forl. wardendof its strokehaving`delivered its blow to the tool 9. The reducedpiston portion 46 has already opened the intermittent pressure port 44to the constant pressure port 42 and the resultant access of pressure tothe larger differential area of the valve through the passage 23 hasreversed the p; sition of the valve. This has caused the opening of thehead end ofthe cylinder 2 to the exhaust passage 15 through the passage25, the opening of the forward end of the cylinder 2 through 'the port35 and the passage 33 to the admission passage 14, and, in the cylinder1, the opening of the head end passage 24 to the admission and thetool-end passage 32 through its port 34 to the exhaust,

6o' the direction of transference of pressure y the intermittent the twocylinders, as

Huid being represented by arrow heads appearingin the said figure. Onthe subsequent and resulting upward stroke of the v plston 7, which isaccompanied by a simultaneousdownward stroke of the piston 6, theexhaust port 58 is soon uncovered and followed directly afterward by theopening of pressure port 48, thereby exhausting pressure from the largerdifferential area of the valve, causing the constant pressure at theopposite end of the valve to reverse the same, as represented in Fig.13, when pressure is admitted to the head end of the cylinder 2 and tothe tool end of the cylinder 1, as depicted in Fig. 13, acting to drivethe piston down and the piston 6. up. It will be seen that thisarrangement enforces the non-synchronous and out-of-step operation ofthetwo tool units, causing each to counteract to some extentrthe shock orimpact of the other with reference to its effect upon the containedcasing, although, of course, without in any way affecting or decreasingthe effectiveness of the hammer blow of each tool. If it is desired tothrow both cutting units out of operation, the regulating valve 38 maybe turned to the position represented in Fig. 14 where the intermittentpressure passage 23 and the constant pressure passage 40 of the cylinder2 are closed, as is also the pressure passage 25 and the tool endpressure passage 33 for the cylinder 2. In this position of theregulating valve, the controlling valve 16 will move to the positionshown in Fig. 12 and there remain, for the hammer 6 after concluding itsforward stroke will then admit pressure iuid through the intermittentpressure passage 22 to the large area of the controlling valvemaintaining the latter in the position assumed (Fig. 12) and stoppingfurther movement of both pistons until the regulating valve is againturned'back. On the other hand, if it is desired to operate-the hammerpiston 7 alone the regulating valve 38 may then be Aturned to providefor the conditions represented in Fig. 15, where the several pressurepassages 22, 39, 24 and 32 leading to the cylinder are closed, while thecorresponding passages leading to the cylinder 2 are held open, therebythrowing out of operation the piston 6 within the cylinder 1, whilecausing the Vsole operation of the piston 7 within the cylinder 2 as asingle tool. Under such conditions the valve 16 is moved `to thepositioxr shown in Fig. 12 by admisin Fig.l9, the shape of -'llheregulating valve 438 may be of any suitable construction and located inany selected position on the toolfbut herein I have constructed the sameas represented in Figs. 8-11 and arranged the same transversely the toolbeneath the valve 16 as represented. in Fig. 2. The valve as shown isprovided with two piston or barrel portions 63 and 64 connected by anintermediate flat portion 65. The latter lies adjacent the passages 24and 25 in the valve block, as best shown in Figs. 1-4, so that in oneposition the said passages are bothleft free and open (Fig. 1), inanother the passage 24 maintained closed and passage 25 open (Fig. 3)and in the third position the passage 25 closed and the passage 24 open.The barrel portion 63 is provided with apertures 66, 67; and 68 which,with the valve in'position., alinewith the passages 23, 32 and 39respectively. The barrel portion 64 likewise is provided with apertures69, 70 and 71, which with the valve in position, are adapted to alinewith the passages22, 33 and 40 respectively. ,The shape of the apertures66 and 71 is shown the .aperture 70 in Fig. 10, and the shape of theapertures 67, 68 and 69 in Fig. 11. This valve Jormed as disclosedprovides for the desired regulation of the pressure passages, which hasbeen described with reference to Figs. 12, 14 and 15. rl`he end of thebarrel portion of the valve 64 is provided with a projection 72 (Figs.

2 and 8), which' is embraced by the. forked end of the valve stem 73,the latter passing through anl aperture in the threaded cap 74 (Figs. 2and 16), and provided with the external regulating lever 75. The leveris provided with a thumb or linger piece 76 carrying a slidingspring-pressed pin adapted to engage with any one of three notchesformed inthe exterior face of the valve'block (Fig. 16), whereby it maybe moved to a central position represented in' Figs. 2 and 12, or to aposition against the stop -7 8 to throw out of operation both cylinders(Fig. 14), or againstthe .oppositely disposed `,stop 79 to throw out ofoperation the cylinder 1 (Fig. 15), the spring-pressed pin acting toVretain it in its assigned position.

scribed and particularly in conjunction .with

the control which provides Afor the joint or intensa 7 be controlled Tobetter understand theV utility oil-the' Thisapplication of the tool isillussole operation of these tools at will, it mayoftentimes bedesirable to turn the tool freely and at will, thereby to .direct the action of either individual tool accurately and eiiectively with referenceto the work. For example, in its application to a stone surfacingmachine,lwhere the tool is sup orted.-

trol the action of the then operative units.

In order that the tool-actuating device described may be readily 4turnedwithin its holder to suitably adjust or aline the cutting tools, I haveprovided the instrument'with a `swivel support in its holder, whichlatter herein is represented (Fig. 17 by the adjustable tool carriage 80of a stone working machine. For this swivel sup ort I have provided theend piece 13 with a tubular extension 81 which is supported forrotatable movement within the sleeve 82 formed upon the carriageand`preferably upon the ball bearings 83, whereby the instrument may beturned at will during its operation.

-The upper end of the tubular member 81 has suitable connection throughthe nipple 84 with the source. of fluid pressure `rsupply (the .latternot shown) and interposed between the latter and the nipple is provideda suitable" form of throttle valve 85 (Fig. 18) by which the admissionof pressure may and the operation of both toolactuating units stopped atany desired time. The end piece 13 is provided with lugs 86 throughwhich pass the bolts87, the latter at their opposite ends also passingthrough' the lower end piece 5 and acting to clamp between the latterandthe end piece 13 the venient means for locking in the threaded valvecap 18 )the head of the latter (Figs. 1 and 5) is cut with a pluralityof transverse grooves 88 within one of which the adjacent bolt 87 isadapted to lie when the parts are assembled. rllhis obviously preventsthe turning of the valve cap until thebolts are taken out and the partsseparated, when the valvecap may be again turned.

In order to provide means for turning the instrument about its swiveledsupport the former is provided with a handle 89 (Fig. 5) which (Fig. 1)encircles and is bolted at either side of the lower end of the cylindercasting to a plate 90, the latter fitting into a recess-formed in thecasting.

ln the particular application of the instrument toa stone surfacingmachine as v cylinder casting and valve block. As a con-l any suitablemeans. Inits operation, there-- z closed duplex hammer tool in detailwith' represented in Figs. 17 and 18, the toolholding carriage 80 is.provided with suitable rollers 91 adapted to travel along the radialsupporting arm 92, the latter comprising'a pair of suitably joinedtrack-forming members, the handle 93 being provided on the carriage toadjust the tool-holding carriage along the arm. The arm 92 receivessupport from ,a central carrier or holder 94, the latter being slidablymounted upon the upright supporting standard 95 as lby the barrel piece96 shown, so that the carrier may be adjusted vertically to any desiredheight. The vertical adjustment 'of the carrier may be effected in anysuitable way as by the rope or cable 97 whichpasses upward over theoverhead sheaves 98, thence downward to a position where it isaccessible to the operator. The carrier 96 has swivel attachment to thecolumn so that the operator by moving the carriage may swing the latterwith its arm through the arc of a circle, and, in addition to the radialadjustment of the tool carriage itself'along the arm, thev latter maybeadj'usted longitudinally with- ,in the carrier and upon the rollers 99and clampedor held in its adjusted position kby fore, the tool uponitscarriage may be moved v to any position over the surface of theunderlying block of stone and the instrument turned radially upon itsaxis, wh11e,at the same time, the regulating valve, as de-y scribed, maybe utilized to so govern the action of the instrument as to actuate thetool-actuating units either jointly or solely.

I'have described the action of the disreference to its use upon a stonesurfacing machine in order that the mode of operation may be more fullyunderstood and the coordination between the various elements of controlmore easily comprehended. My in- -vention as herein described andhereinafter more broadly claimed is limited to no particular applicationor use.

It will be obvious that a duplex or other multiplex -tool may beemployed, wherein the reciprocal 'or non-synchronous movement of thetool-actuating devices may bef secured while employing more than asingle valve-controlling means, and that with such a constructionregulating means either simi- 'lar to those described or otherregulating Apriate cylinder,

to the particular form herein disclosed or to the details ofconstruction which, for the sake of explicitness are herein fullydescribed and illustrated, but that extensive modications and deviationsfrom the illustrated construction may be made without departing from thetrue spirit of the invention.

Claims:

l. A pneumatic impact tool or hammer having a pair of piston-hammermembers adapted to reciprocate each within its approsuitably held toolsadapted each to receive the impact of one of said hammer members, asingle controlling valve for said hammer members having differentialpressure areas, means for maintaining the smaller dierential area of thevalve constantly exposed to pressure fluid to press the valve constantlytoward one position, suitable admission and exhaust passages,pressure-fluid passages controlled by the valve and leading to oppositeends of each cylinder, the valve. in one position being adapted toconnect the head end of one cylinder and the tool end of the other tolthe admission, and the tool end of the frstvcylinder and the head endof the other cylinder to the exhaust, and in its reverse position toeifect reverse connections, said cylinders being each provided with aconstant pressure passage and an intermittent pressure passage havingports opening into the cylinder at `or about the same point and adaptedto be placed in communication with each other on forward pistonmovement, thereby to admit pressure to the larger differential area ofthe valve, an exhaust port for the forward endl of each cylinder adaptedto be uncovered on rearward piston movement, a second port connectingeach cylinder with its intermittent pressure passage and adapted to beuncovered by the rearward piston movement, thereby to exhaust thepressure-Huid from the larger differenti al area of the valve and toreverse the lattermand a regulating valve adapted to control the'pressure passages of the two cylinders, said valve in one position beingadapted to close the intermittent pressure passage and constant pressurepassage of one cylinder, while leaving open .the intermittent pressurepassage and constant pressure passage of the othercylinder and alsoleaving open the pressure passages leading to the opposite ends of bothcylinders, in another position additionally to close the pressure-Huidpassages leading to the opposite ends of the first-mentioned cyl-Ainders and in still another position to open the intermittent pressurepassage, constant pressure passa e and cylinder pressure passages forsaid rst-mentionedcylinder while closing the corresponding passages forsaid other cylinder.

`2. A pneumatic impacttool or hammer imacat having a pair ofpiston-hammer -members adapted to reciprocate eachwithin its appropriatecylinder, a separate actuated. tool foreach hammer member, a single'control, ling lvalve for, said hammer members having differentialpressure areas, means for maintaining pressure fluid upon the smallerd'iferential area of the valve to press the latter constantly toward one-posit1on, Huidy supply passages controlledby said valve to supplypressure fluid for moving the hammer members in opposite directions '1none position of the valve. and reversely in 1ts reverse position, anintermittent pressure passage leading to each cylinder and communicatingwith the larger diil'erentlal area of the valve, means for placing saidpassages incommuncation withva supply of pressure fluid on forwardpiston movement, and means at will for closing the intermittent pressurepassage for one cylinder, thereby causing the joint operation of thehammer members in opposed step and the control of the valve through onehammer member or for cutting off the operative supply of pressure iuidto one cylinder at will, thereby to actuate a single hammer member only.

3. A pneumatic impact tool or hammer having a pair of piston-hammermembers adapted to reciprocate each within its ap-^ propriate cylinder,separate actuated tools adapted to receive each the impact of one ofsaid hammer members, a' single controlling valve for admitting pressurefluid to cause said hammer members to move in 0pposed step, pressureluid means for controlling the reversal of said valve through pistonmovement, and pressure fluid regulating means for withholding operativepressure lHuid from one cylinder while continuing to supply the otherthereby to throw out of operation one of said piston-hammers at willwhile continuing the operation of the other.

4;. A pneumatic impact tool or hammerhaving a pair of piston-hammermembers adapted to reciprocatey each within its appropriatecylinder,asingle controlling valve therefor, a pressure fluid passageJfor each cylinder adapted to be controlled by its respective piston forthe passage of pressure fluid to reverse the valve,'pressure fluidregulating means to close one of said pressure passages at will, and,atthe same time, cut o the operative supply of pressure fluid to thecorresponding cylinder, or to close one of said passages whilemaintaining the operative supply ofpressure fluid to each cylinder,thereby to eect the sole operation of one of said hammer members orjoint opy eration of said hammermembers atwill.

5. A pneumatic impact tool or hammer having a pair of piston-hammersadapted to reciprocate each within its appropriate cylmder, a singlepressure-actuated controlling valve to cause said piston-hammersnormally to reciprocate in opposed step, and valve means for withholdingeiec'tive power from one of said hammers while contmuing to supply theother thereby to throw out of operation one of said hammer ,members atwill, while continui-ng the operation of the remaining one.

6. A pneumatic impact tool or hammer having a pair of piston-hammermembers adapted to reciprocate each within its appropriate cylinder, asingle valve for controlling said members and causing their re-,ciprocation in opposed step, andvalve means for withholding effectivepower from one of saidmemberswhile continuing to supplythe other therebyto throw out of operation one of said hammer members at will whilecontinuing the operation .of the remaining one.

7. A pneumatic impact tool or hammer having a pair of piston-hammermembers adapted to reciprocate each within its appropriate cylinder, asingle controlling valve, and valve means for withholding et'- fectivepower from one oi said members while continuing to supply the otherthereby to 'throw out of operation one of said hammer members at will,while continuing the operation of the remaining'one.

8. pressure-fluid tool-actuating device having a plurality of4tool-actuating units adapted to reciprocate non-synchronously, asinglecontrolling valve for controlling the reciprocation of said units,and means for withholding effective power from one of said units whilecontinuingto supply the other thereby to throw one of said units out ofoperation at will.

9. A `pressure-fluid tool-actuating device having a plurality oftool-actuating units, a single pressure-iiuid-controlled valve forcontrolling the recip'rocationa of said toolactuating' units, and valvemeans for directing the pressure Huid to one or the other of said unitsthereby to operate said units jointly or for throwing one out ofoperation at will, while continuing the operation'of the remaining one.

10. A pneumatic 'impact too'lor hammer having a plurality of hammermembers,

means for applying power for operating.

' sides of each piston hammer member alternately with the live pressurefluid supply and the exhaust passages to cause reciprocal movement ofsaid hammer members.

13. A pneumatic impact tool or'hammer having a plurality 'of pistonhammer members and provided with a live pressure fluid supply source andexhaust passages and a single automatically-acting manually-com'trollable means for connecting opposite sides of each of said pistonhammer members alternately with the -live pressure fluid supply and theexhaust passages for causing an out of step reciprocation of said hammermembers.

14. A pneumatic impact tool or hammer having a plurality of hammermembers, an actuated tool for each hammer member, means for applyingpower to both of said members thereby to provide for the operation ofsaid hammer members -jointly, and means to withhold effective power fromone while continuing to supply the other for the sole operation ofv oneof said hammer members at will.

15. A pneumatic impact tool or hammer having a pair of piston-hammermembers, separate actuated tools adapted to receive each the impact ofone of said hammer' members, means for supplying. power to both of saidmembers to cause their joint operation and means to withhold effectivepower from one while continuing to supply the other for throwing out ofoperation one of said hammer members at will.

16. A duplex pneumatic impact tool or hammer having a pair of cylindersand a pair of piston-hammer members, a differential pressure-actuatedvalve for controlling the same, an intermittent pressure passage openinginto each cylinder and adapted to be placed in communication withpressure fluid on the forward movement of the piston to admit pressurethereto and thereby reverse the valve, an exhaust port adapted to beuncovered on rearward movement ofthe piston, a plurality of portsopening into said intermittent pressure passage and adapted to be placedone or another in communication with the said exhaust port on therearward movement of the piston, and manually operable valve means forrendering one of said intermittent pressure ports eective or ineffectiveat will. l i

17. A pneumatic hammer having a valve chamber, a threaded plug closingthe end'of said valve chamber, and a tie-rod for said hammer, said plughaving a suitably recessed head adapted'whenvthe parts are assembled tobe engaged by said rod and thereby locked in threaded engagement withthe hammer.

18. A pneumatic hammer vhaving a valve chamber, a threaded plug closingthe end thereof, an exteriorly grooved head for said plug, and a memberupon said hammer adapted when the vparts are assembled to engage agroove in said head, thereby to lock said plug in position.

19. The combination with a pair of cylinders of reciprocatory toolactuating members, one in each cylinder, separate actuated tools adaptedto be actuatedy each by one of said members, a single controlling valvefor admitting pressure luid to move said members in opposed step,pressure fluid means for controlling the'reversal of said valve throughpiston movement and manually operable fluid regulating means forthrowing out of operation one of said members at will while continuingthe operation of the other.

20. The combination with a pair of piston members adapted to reciprocateeach within its appropriate cylinder, a single valve for controllingsaid members and causing their reciprocation in opposed step andmanually operable valve means for throwing out of operation one of saidmembers at will while continuing the operation of the remaining one.

21. The combination with a'plurality of tool actuating units adapted toreciprocate non-synchronously, of a single controlling valve forcontrolling the reciprocation of said units and manually operable valvemeans for throwing one of said units out of operation at will.

22. The combination with a plurality of tool actuating units of a singlepressure fluid controlled valve for controlling their reciprocation andmanually operable valve means for operating said units jointly or forthrowing one out of operation at will while continuing the operation ofthe remaining one.

23. The combination with a plurality of reciprocatory tool actuatingImembers of a single controlling valve for the same and means forwithholding operative fluidfrom one while continuing to supply the otherthereby to operate said members either together or one alone.

In testimony whereof, I have vsigned my name to this specification, inthe presence of two subscribing witnesses.-

GEORGE H. GILMAN. Witnesses:

J A. BRUCE, E. J. BRUCHARD.

